When monochromatic radiation of intensity I falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2I what is the number of emitted electrons and their maximum kinetic energy?
1. | N and 2T | 2. | 2N and T |
3. | 2N and 2T | 4. | N and T |
A helium-neon laser produces monochromatic light of a wavelength of 667 nm. The power emitted is 9 mW. The average number of photons arriving per second on average at a target irradiated by this beam is:
1.
2.
3.
4.
Waves are associated with matter only:
1. | When it is stationary. |
2. | When it is in motion with the velocity of light only. |
3. | When it is in motion with any velocity. |
4. | None of the above. |
A particle which has zero rest mass and non-zero energy and momentum must travel with a speed:
1. | Equal to c, the speed of light in vacuum. |
2. | Greater than c. |
3. | Less than c. |
4. | Tending to infinity. |
If the following particles are moving at the same velocity, then which among them will have the maximum de-Broglie wavelength?
1. Neutron
2. Proton
3. -particle
4. -particle
What is the momentum of a photon in an X-ray beam of 10-10 meter wavelength?
1. | \(1.5 \times 10^{-23} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}\) |
2. | \(6.6 \times 10^{-24} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}\) |
3. | \(6.6 \times 10^{-44} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}\) |
4. | \(2.2 \times 10^{-52} \mathrm{~kg}-\mathrm{m} / \mathrm{sec}\) |
The energy of a quanta of frequency Hz and will be:
1.
2.
3.
4.
The number of photo-electrons emitted per second from a metal surface increases when:
1. | The energy of incident photons increases. | 2. | The frequency of incident light increases. |
3. | The wavelength of the incident light increases. | 4. | The intensity of the incident light increases. |
A photon of energy 3.4 eV is incident on a metal having a work function of 2 eV. The maximum K.E. of photo-electrons is equal to:
1. | 1.4 eV | 2. | 1.7 eV |
3. | 5.4 eV | 4. | 6.8 eV |
A photocell is receiving light from a source placed at a distance of 1 m. If the same source is placed at a distance of 2 m, then the ejected electron:
1. | moves with one-fourth of energy as that of the initial energy. |
2. | moves with one-fourth of momentum as that of the initial momentum. |
3. | will be half in number. |
4. | will be one-fourth in number. |